Couple of problems here. :) "Behoove" is always used in a positive sense. "It behooves us to..." roughly means "it is proper(right) that we..." But since this girl is already being improper and disrespectful, it is impossible that she is further "behooved" to act rude... which is also close to impossible in itself. The second issue is that "behoove" is a very formal verb. You'd never use it in a family or domestic setting, unless you were acting unusually "proper", or making a joke. "It behooves us to acknowledge and respect her life's work." - proper usage. "It behooves me to drink myself stupid this evening." - joke form! :D